EisenEx
EisenEx is the name of the experiment that was carried out with the research ship Polarstern of the Alfred Wegener Institute in November 2000 in the Antarctic Circumpolar Current . It was investigated to what extent algae growth can be influenced by fertilization with iron sulphate and how this affects the biosphere . On January 7, 2009, the Polarstern ran out of the 70-day follow-up experiment LOHAFEX , which triggered severe criticism from environmental protection organizations and a dispute between German ministries.
target
Studies of Antarctic ice cores have shown that the ice ages of the CO 2 content in the atmosphere was lower than in the warm periods and thus into the ice ages more CO 2 was tied in the seas. At the same time, an increased iron-containing dust entry into the oceans during the ice ages was found. The algae play a key role here, absorbing and binding CO 2 from the air as they grow . Investigations of the deposits on the sea floor also showed that there must have been a real algal bloom during the ice ages, especially in the southern polar sea.
The aim of the previous and current experiments is to better understand the role of iron in the global climate system. It is already known that the introduction of the micro-nutrient iron leads to intensive algae bloom in waters in which there are in principle sufficient macro-nutrients available.
Whether this form of sea fertilization with increased iron sulphate supply can lower the CO 2 content in the atmosphere in the long term and thus counteract global warming requires further consideration.
execution
The target area was a stationary oceanic eddy in the Antarctic circumpolar current. Ten tons of an iron sulphate salt (lawn fertilizer) and small amounts of a marker ( sulfur hexafluoride , SF 6 ) were placed in a spiral shape into his eye with little flow . The local limitation of fertilization played a major role so that the results obtained can be compared with those from unfertilized marine regions.
observation
Within a few days an increased growth of the planktonic algae , especially the diatoms , was found. The bacterial population was also stimulated by iron fertilization.
Overall, in the three-week experiment, a five-fold increase in biomass compared to unfertilized regions was observed.
The fertilizer carpet, originally 50 square kilometers in size, has expanded to 1,000 square kilometers over the course of three weeks due to the currents.
Result
The targeted addition of iron sulphate can artificially influence the growth of algae and thus the binding of CO 2 in the oceans. It can be deduced from this that the productivity of the seas depends on the entry of ferrous dust from the continents. The functioning of the biosphere and geosphere as well as the atmosphere and oceans must therefore be viewed as a coherent system.
The extent to which large masses of CO 2 can be bound by fertilization in the oceans and what effects this has on the global ecosystem must be shown in the following experiments.
According to a report in the New Scientist magazine , iron sulfate promotes the growth of the diatom Pseudo-nitzschia , which is known to produce the toxic domoic acid and thereby cause the poisoning syndrome known as Amnesic Shellfish Poisoning (ASP). This article cited researchers who recommended further detailed research because the ecological effects of large-scale iron sulfate fertilization are not yet understood.
Individual evidence
- ↑ Floating iron: Scientists do research in the South Atlantic. Possible results are already causing a dispute in Das Parlament , issue 06-07 2009
- ↑ Michael Reilly: Is ocean seeding dead in the water? New Scientist , June 14, 2008, p. 7; published online under the title "Ocean seeding fails the acid test" ( memento of the original from October 29, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
